SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '051d3fd7812568fa463a813ccf5e17d7ad62d32c5504428fe7451ade045966f6' 
  AND token = '9yu2pSl2YMGmAZIMk97NJ3v1aus1GukqYd6JjTzuGaY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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