SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'cb699bafd3a8f5ec6b4eb0229c678ff9f909743169568a61c3d1e5602a53721a' 
  AND token = 'DbakbrMo0Oz5RCpfTLUOTzV7OvR2ki/77yobQmp9jXI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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