SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '31777550b31f494811bacc4e094b80325cf9653214e2a2a7b0cfb65ba5f0d944' 
  AND token = 'yzlaOKPFy28vUrcdGdvJS+2L1mmtCsNw/KrsfYG0OsM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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