SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '73574235f1d3dbf37555cbfeeef9ea75c686af735af416a70d1e841e99b265fd' 
  AND token = '4ErfwzmMK3oP0Tungah/UJzR6V6iAbzON9Yd/2xpqH4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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