SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '1f6a3ddcf2a19f6fd08c131656d8af66bc901cc95850bac95edef0b1b2e55523' 
  AND token = 'bui38yfxTvHT4mOpiHDqCI3OqlIFMkJPGDZ5UxnqfUc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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