SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86fe7c475e1c63ff11ca32b2ec462780d1cecb853cacd94127fde0119b50c18e' 
  AND token = 'P+W8q1FfwUF8wzPMcoPoFDVQZf0Fntp75ZQLYGz5c5Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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