SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3f44e4ae1acd94b75dd047c5e26ec0d2d09a0d2eb5d6b2ed41ec963d9cb5c0a' 
  AND token = 'UBiupKgy3jnZaiaMHLGdAfcV6SunU1Js6kb85qCCNS0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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