SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e90a77cb389a14edd3429d0215994c16736b192280437bbb2f08d12366b06c8' 
  AND token = 'XV1dx0fG1vgEj6OWvH/4Ls7xAYwFo+eYDR/C0wZYN9U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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