SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5762cf097b0aa2b98fdeb88a192c118c0a4363edfbbfa76285f211c4c9d6733f' 
  AND token = 'F7Nv9ubm8+DwvwENA0lLZyKnPPGbvaZ0CDlyhQtXmzY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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