SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7940b64ee56bfe8c2e75d4324d90c9f6758c93560eb06ba03158cdc00ad0dbaa' 
  AND token = 'oyviQ6N1wWpATrhKF9w1NbCaq3Eu+z87WhXwpuHn1yk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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