SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '9089ff5bf32212d34faa78b24245f06e602492ebcf73f6f4afcc39ba86589974' 
  AND token = 'OBiFLruR14gVeJ67Yx+oRK9i4gHaooJWiSBxHNHRAwk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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