SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de8e3eb27fc09a6e7275aa05be54fc857e81ae7a0d46ecc38203faf7b880b5f1' 
  AND token = 'SRERM82LzXb1VOV7BuuVlYCl9vcyvFzd4X+FOkzIlBA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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