SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6afa07eace574ecea19a63b40d1b95b702b709cc31783d9a19184418bf3a1fd7' 
  AND token = 't/BmyxnnffQOfmBiyq9EyX+USHMSmCF8zf92immeFHo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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