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SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a1236c70d056a4aa9c44a6d5a3444493dd3dacd8dc10ca440daf8ab71d1d3a5d' 
  AND token = 'uL/29Rp6EGUtxL+VR3OxEY4MKf8shjDNzlaH/4zZuGg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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