SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '876c37ba40bbd1d56719e1a21e9c0884fe1a5d07ade42cda81d06eb7e4dccf82' 
  AND token = '5PCMTclKMbDl5MXReMq9M1MZwRur+bl+GuXT9E0PlrU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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