SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'dcf1101418d1d353bc9fe8206b88f2a863805863b45d6034342dba1354d9980a' 
  AND token = 'YAKNEB5D3Oepqa0F8bVxn5I6i4kI7/hnWrRhINAyYRk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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