SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '85e2c43d47a5a7782eed24992aef55a8b7b4eb92500b7c9b91519358d2d0aab4' 
  AND token = 'yyYdnorZBTjyp1IlZMEVguKW8V7Q2RCTob0kGZyQXAQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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