SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f1cabb4c662ceedea632a239ae6ca4501feb44a01e3e9d437923884eea3bf0f8' 
  AND token = 'N4ioU3OOPeo5lf6ChFBWf7EpCYgQVlMxjXK37QuiRTI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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