SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '59a371e3bb445c953d859c6edc93397d1df3ace56af1afd85ef225b771cae27a' 
  AND token = 'ayG4B79egUXixaL3Wtxw+iGoFv2M3t3ZPAa3mpZoXFY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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