SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a3a6ea276a0101d6400d0b9e3ab6d38c15281cbf61168626358448654e5c84ab' 
  AND token = 'lked3wp7xzwYnonKoSXtukCm2fDi5oDSp2zepZna2Bc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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