SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b730f77d1a73a7413b49eb587ca811324dfd863ef94c9561075ddc610c81ef6' 
  AND token = 'L2F7ZKjShZgDYGkEulWtAua0ytZ8oKGOXUu+pxOSogY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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