SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86743fd896b73832dfc5086c94e8393152ace29f48905c74df58f74fac944fdf' 
  AND token = 'p4X5jkoKRQ+0UK4E2JIjehdshqvJ9Ut+0Y6cbcvP8dA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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