SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e48fe5df9da4d37179848a973415743d0a708a2486c49379a2457d338e507437' 
  AND token = 'gl4jNZPaErPQ0GDZ5VPspH2Vc7pv8TE3/qPLEobUwJA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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