SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0fea83a6af7c1bb3e9e6f39c46004329be628ebf86ad5b060f6083f4ae02d25' 
  AND token = 'lU7x02zP6fdvU0uNfQLAVwa5p5rom4m+GG7eLsIhV4o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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