SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b66e250bfe6963a10f79223b81ca736837a5678f5dcfcccf1945a7f1328b6294' 
  AND token = 'n08HxS+BMzPlQMeopxMWNcoDAA0joWmmvSKFUoGQfKI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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