SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19edc68bc66c085bb52ab512fdafd023ba77855e7d1fb9c638389bb8dd628d2d' 
  AND token = 'BqGbomTgmpPeqvwvpzq68HbcYxWWht4Wv2gABUK/u+I=' 
  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"
    }
  }
}