SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e73d68c88700def5156635a0807fdb7fbc53fa9735d9c20851b0e431d6b07d56' 
  AND token = 'N1MqZEPDerCGgwZk7vkHqh2e8jKXM05pKjxEXz3DkTY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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