SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c570fc7ae182f7033fe14b1343e7a787a242a361eefcaefefda260648ee32c99' 
  AND token = 'mpq99tBlPVBBkZvGIOVqfnQCwAqNh2x/HCfb8tV7pTU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

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