SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '046a8f32006d0c89702c75d0a06f010b367366b372503f554a945501fd0f9f94' 
  AND token = 'cWlJF7voa+Gt+ek4i42XE15oPhSGnh0YvEEPCzeQEJE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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