SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7840d6053c3e2a48982e3301d53b5885f21294e7a6f1d4211155152ba15c9a7' 
  AND token = '6izpHepqsjUDGHHrny2T86kJGFTRKx8ksyq4BWX8oCg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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