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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4f6bf04f0e3e1c838ce935235222c9dbdd89f392a671d5b83bb6e4f64d5e6b5' 
  AND token = 'mdkV4Rpzk8LmymU9JfKVmTSV769w3dtr+PBSlk0bGPk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}