SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb55b1705d0e029e562019b5865b5fc772c08d284ddebeb9d43b7805ebe117c9' 
  AND token = 'r23aeowhvfj1Vnw9YhrPMAWXewmSA/ATxpPj19s8ahk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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