SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '188137a2fa363e2fe8fd309f6681369ea3e0f9ac792c7cf5d4da2a2c638908d9' 
  AND token = 'uSdGHb1hIInM+qOWtROwqF8V2tLjBlN8NYHZILPC5pE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}