SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38ce0f556235c58e7959578cc4d87a720d253065a6341535a12c22629f1b0b6c' 
  AND token = 'I1YPB6fARa1gPoSnGpDvVpd08sN95ezDxmrbMaYfYco=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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