SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f902b4efeae5e1a70a070944c7d31c2b53d80e53109852847eedbf25f274b2eb' 
  AND token = '9yKvC+CGDFtpmaJBUPS3e10QTBIUxKRsZAEe/qAZ/Uk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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