SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb9542b990db73faad46da8463cf41696a1a6884857ac1dbca58984a4fd2dc51' 
  AND token = '+oVO5uI8/kjoMN3yUcL4qoNcTFxfcDJPHhsmyj4gM2E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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