SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e0be04f665cf042169168d8526da5bd9ec5a905d031400e93198cac36888c22' 
  AND token = 'gHqimjGUkBZrxFE4VmGChhsyLbktf0AZgwRUbimwYpQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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