SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '13b4ceba0c04e0c21bab6df42758745b5c47f6bb2f962736028ed0a840384623' 
  AND token = '79yiLH0oOisg5Sg1X3KUzrgp8hrGP1i0JEZFNucuiMo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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