SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c447f8aa8111189b40b00b8826594a0bc33d624520df9a7da5bc3903e1e6f318' 
  AND token = 'Qw+ubqvvIVYZPef0H3bRGnCHKXl9YF74r+jDeTnWkcs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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