SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e89b57b6564c087f5afcf617b64f512c6f6775e01881417a5304b59356ca9ca4' 
  AND token = '+RXnKOS2QCCR/W6c7nvV3zFXn/I+VPXXWhVdJS+YE+Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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