SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b2080afcacbe98016f8f042d879404b72c3e878a5ffc4a3162b2a957a8147822' 
  AND token = 'Dzaj7/GvlGIgb25VFERQ31A6HXKROYW8/Kdu2xHjAcM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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