SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'db64796c0e102dbcbc5090029a4e8899b90985d730467f0946e67ef3a8a6838f' 
  AND token = 'Bli8VrJHwfSDhl+Jv3hKmiF+UYzeR1zolfnoj50Oc9c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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