SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa48a7df836455bce750c2f83659abc8b0b3d2c4cb27d0a544a110fbd9a7fcdc' 
  AND token = 'YIR6jBxqw8eAb/0sXumrUsRiT0hw5OqHVM6JVQbDugY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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