SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68722fb85e0bb1b6d57f5058c8e4bc1328bf15e1125afef39e31311c938b4882' 
  AND token = 'C658bs4GkPhbZmlpQ15jvXQVPRl7VPgntT3MI/8Uv5A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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