SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af7661eced97aeec956a46815fa55fbd52c104837cb92ca976776a93bc62c22b' 
  AND token = 'jdM5Wf1zqLVGuLu4Igwlcijpy+h6uYHDwmvoq58Z9bU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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