SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4bc1eb3e9d48228f9e35ff7d083de91a3fd58b83159363867967275f46804ca' 
  AND token = 'cIxYvR+Bv0lX3zawqziHtgp1WIiptcIzXA8SSPuMmB8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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