SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a404b58d0e785542b8e15d18602a6a3ee383f431488f59128ba482fb9b1d8db' 
  AND token = 'BJpHRdtoBfaOMYuS2oZaZgNqi+2DQtBsaJ1uYEDRobw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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