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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3abcf3a642031ad82a1303114491c2b73bdc233ea3cc281ba4f4b3bb789b210' 
  AND token = 'TJWL8Dej/ZIDGPZTJiOibFrepi0oVtyaCzXcLcM/MMk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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