SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'decf41fb040506d3121d7e8c64c9af889d11b229c51d9a90a403b7a36e0dc4d5' 
  AND token = 'MC9o6pRp2Bjzw0RCdrBiiCfknQqsS4H2fYjFAhYo+Ug=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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