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SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a4a6f924d627a26661dd7a28d80bfbefd20cc2e7096c00c8150b9ee24ab3a2c6' 
  AND token = 'md638qrLbIkrptQ9O1DI+lFOF+Rs+aLrHBhXfWO3+TU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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