SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'c8a165f5b10401ff8a324e0deff6f8222d7394846111fbb9a791c55b8a456021' 
  AND token = 'F3kqNzY+e2v3T45uL5+VQ94fAbgoqMo4mGRdyWWBuzI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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