SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c36e0f8c6e26766d183c49a45229a67400368f8c1e35032369b65a32071cbb97' 
  AND token = 'rBBHffGq+XTSBed5Ia4LPFgvTINLcE+WkQQV2dd+DVY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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