SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd15065777d4d4049268e3ad6622101b98b2d8e02e836661f6ebc1e4998b73e99' 
  AND token = 'avUjMxcX407nUsusTsraEQllGZ9PySubTFiso6Tyekc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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