SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b61f205b6a785ca426272f894bfa6eea6f0d8e9107a17ed36cd447efb44115ae' 
  AND token = 'zY+kFRvZRhKHPDFsOSAq+/K1KkGXgCFmLJf7NaAiEZ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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