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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3df6e43a4c55dbccfcba07d450ef09e2ebe3581c4d2155c5ccacd6e7e43034d6' 
  AND token = 'TFaO9e7tjOtSI8o1pbYC9HjLUAfwxbAcSdvm/0WeDXg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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