SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55adb759665f6dfdbbb5d69f0104e335a5166b44317ba281be192ab09f6d217e' 
  AND token = 'c9KCp30sotIeyK+cfv41YpalnKG4OG8iLZsk1yJfd5o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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