SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef577159bdf2aed3a02cac6566db7a8c4bda8ffcc34f6649d4e640e52f958842' 
  AND token = 'rL3sny5pHFhJC/GQSblqigzfgFRHLs13/xetpqCBq4Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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