SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc0af7328f46ef4a301c6ebb7d126618f77955406d732d5eab08055039b6ea96' 
  AND token = 'lJLs135dThnezG+pmjarDKgkhKhx4D4yBveE5wy+u6s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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