SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4cd279b8605c35d40fe11f6fb8b397c651ef96d863aa6152332957d43735cca7' 
  AND token = 'JLN/hquq50oKha+jx3XMUBSv/Gl7d0KpUqbstze6YJo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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