SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '145aa6705c139953cafcc5c135dabd75210df749d258dce6ea0289a555917530' 
  AND token = 'YkRD7lVn+3A5LUXWcy91nFv9x9NdruMTjG48Vw3jXJE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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