SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9302cebfef204529798e818525e44e25864c1003beaba21ea1d061f9931162c8' 
  AND token = 'ZaL5o99BgJE43MYfj6e4m7UGTlVZl8kEG4OTk36xzLw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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