SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7f3306683a865fdec1edcef2bb9b202c7fe7c8d664323b527a220b8550dda39' 
  AND token = 'BGHdY7zSueM50FhcJtzaPeP5k0Gfj3iiWUzZPDYlWR0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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