SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9bcb0200e8df649f68f969a56759be2769f27e6f0693a4277b8efdddbeb2365' 
  AND token = 'LFH2UqGXerxjhekc/Kp//iz1by5+MJZMxUvn1uu3Ius=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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